综合应用分支模型和天线阵理论对大豆冠层后向散射系数的研究

Study of Backscattering Coefficients from Soybean Canopy by Combining Branch Model and Antenna Array Theory

提出了一种新的方法来研究大豆冠层的极化后向散射系数。这种方法结合分支模型〔1〕和PACT模型〔2〕的优点:前者强调植物结构和相干效应的重要性;后者则采用天线阵的概念来考虑植株间的相互作用,适合应用于大豆等在耕作实践中通常具有准周期的作物。而且,针对描述轴对称散射体取向的欧拉角和球坐标系统中的仰角、方位角的联系,提出了更符合物理实际的新的关系。由我们的方法预测的后向散射系数和实验数据的良好吻合,证明了其有效性。

A new method is proposed for studying the polarimetric backscattering coefficients from a soybean canopy. This method combines the branch model, which emphasizes the significance of vegetation architecture and coherent effect, and the CP-PACT model, which adopts antenna array concept to account for the inter-scatterer interaction, an appropriate technique to be applied to agricultural crops like soybean where semi-periodic plant arrangement is the norm of agricultural practice. Moreover, in relating the Eulerian angles that describe the orientation of an axissymmetric scatterer to the elation and azimuth angles of the spherical coordinate system, the new association suggested in this study makes more physical sense. The effectiveness of this proposed method is validated by good agreement between the predicted backscattering coefficients and measurement data.